The invention relates to a loudspeaker comprising a magnet unit that generates a magnetic field, and a membrane which is mounted in a frame and which is provided with an electrical conductor arranged in a pattern on the membrane, which membrane is positioned in the magnetic field in such a manner that a force is exerted when current is fed through the conductor pattern on the membrane, which force is capable of setting the membrane in motion so as to produce sound, the frame being provided with metallic cooling members that partially cover the conductor pattern.
Such a loudspeaker is described in U.S. Pat. publication No. 4,264,789. The heat that is generated in the loudspeaker and the heating of the various loudspeaker parts that results therefrom causes the efficiency of the energy being supplied to decrease. By reducing the heating effect, the effective output of the loudspeaker will increase of. Known solutions for dissipating the heat of loudspeaker parts are ferro-fluid cooling, air cooling or convection. Metallic cooling members are used for dissipating the heat in said known loudspeaker.
The frame of said known loudspeaker comprises frame-shaped glass fibre/epoxy frame members, in which the membrane is mounted, and the metallic cooling members are two U-shaped metallic plates provided between one of the glass fibre/epoxy frame members and one side of the membrane, absorbing heat from the overlapping portion of the conductor pattern present on the other side of the membrane. The conductor pattern is an elongate, rectangular spiral, in which the parts covered by the metallic cooling members comprise the ends of said rectangle that do not contribute to the vibration of the membrane. Although no mention is made of this in said publication, it must be assumed that the assembly that is shown therein is enclosed in a loudspeaker housing. A limitation of said loudspeaker is the fact that the metallic cooling members only have a limited heat dissipating capacity.